Surveyed Crowns

Question 1

when would one choose to do a survey crown

Answer 1

• to restore badly broken down clinical crown
• to reestablish a proper occlusal plane
• to create proper rests, particularly with anterior teeth and adequate retentive undercuts for direct retainers and guide planes when inadequate contours exist

Question 2

what is the survey crown constructed for

Answer 2

to provide appropriate contours for the prescribed RPD abutment

Question 3

the survey crown is prepared to accept the:

Answer 3

RPD components

Question 4

what must the survey crown be designed to include

Answer 4

appropriate undercuts, guiding planes and rest seats

Question 5

how are survey crowns planned

Answer 5

• accurate diagnostic casts must be made and analyzed
• definitive RPD design must be drawn
• mouth preps must be planned and executed

Question 6

when are re-contouring procedures done in relation to crown procedures

Answer 6

before

Question 7

when should guiding planes and rest seats be prepared in relation to crown procedures

Answer 7

before crown

Question 8

what are the general considerations for the survey crown prep

Answer 8

• retainer design and what material
• the occlusal and cingulum rests are constructed in metal
• areas that engage retentive clasps can be in metal or porcelain
• guide planes in metal

Question 9

what features should you include in survey crown prep

Answer 9

• prepare occlusal or cingulum rest
• consider guiding planes

Question 10

what lab work must be done before crown prep

Answer 10

• full arch impression of the prepared tooth
• an accurate, properly trimmed cast is essential

Question 11

what should the lab work authorization include

Answer 11

• indicate RPD retainer selected (RPI, RPC) including height of contour details
• indicate the desired location and mount of undercut for retentive arm
• indicate rest details
• indicate material for rest
• indicate other metal ceramic requirements

Question 12

the wax patterns for the surveyed crown should be:

Answer 12

appropriately contoured

Question 13

guiding planes on survey crowns should be parallel to:

Answer 13

guiding planes on the remaining teeth

Question 14

what are the steps of the laboratory process

Answer 14

• the wax patterns for the surveyed crowns should be appropriately contoured
• guiding planes are created and refined using a wax knife in the vertical arm of a dental surveyor
• the height of contour is marked using an analyzing rod in the vertical arm of a dental surveyor
• adjustments are made with a carving instrument
• the position of the undercut is verfied
• a discoid instrument is used to finalize rest seat contours

Question 15

dental ceramics are ___ in compression but ____ in tension

Answer 15

strong; weak

Question 16

if the rest is permitted to bind against the walls of a rest seat:

Answer 16

wedging forces will result

Question 17

what could result in failure of a ceramic restoration

Answer 17

accompanying tensile forces

Question 18

what is done after casting

Answer 18

• crown contours are examined using dental surveyor
• a dental surveyor may be used as a milling device. a handpiece holder is attached to the vertical arm of the surveyor
• a straight handpiece is then secured parallel to the vertical arm of the surveyor in handpiece holder

Question 19

following the addition of ceramic:

Answer 19

crown contours are evaluated using a dental surveyor

Question 20

what should you do prior to delivery appointment

Answer 20

• pick up crown
• survey to ascertain whether lab has given you the survey line and amount of undercut you requested